isoform 3betaHSD2 associates with the inner mitochondrial membrane or outer mitochondrial membrane translocases facing the intermembrane space. Tthis interaction promotes the conformational change needed for full activity. 3betaHSD2 associates with the inner mitochondrial membrane but does not integrate into the membrane. 3betaHSD2 forms a transient association with the translocases Tim50 and Tom22 and with Tim23. This association occurs primarily through the interaction of Tim50 with the N-terminus of 3betaHSD2 and contributes to enzymatic activity. Tim50 knockdown inhibits catalysis of dehydroepiandrostenedione to androstenedione and pregnenolone to progesterone. Although Tim50 knockdown decreases 3betaHSD2 expression, restoration of expression via proteasome and protease inhibition does not rescue activity